Artemisinin, an effective component of the traditional Chinese drug Qinghao (Artemisia annua L.), is a peculiar sesquiterpenoid lactone having a peroxy group. The chemical structures of artemisinin and its derivative artesunate are:
respectively. Artemisinin not only has excellent antimalarial effect, but also is effective to other parasites (e.g. Schistosoma japonicum etc). Moreover it has been found to be immunosuppressive, and was once used in a clinical trial of lupus erythematosus with promising results. With the extension of related research works, it has been found that artesunate, a derivative of artemisinin, has a stronger immunosuppressive activity than artemisinin. It may achieve better therapeutic effects in the treatment of lupus erythematosus and some skin diseases. Although immunosuppressive effect of artesunate is stronger than that of artemisinin, the patients had to take it by intravenous injection in a long term of medication, so it is not convenient in administration. Cyclosporin A, a commonly used immunosuppressant, is expensive and deleterious to kidney and liver, so that some patients can not persist in the medication. Thus, the present inventor carries out a study for finding more effective and safer immunosuppressants.